Drag Flashcards
Describe Drag
The aeronautical term for the air resistance experienced by the aircraft as it moves relative to the air.
What happens if drag is reduced?
The lower the drag, the less thrust required to balance it. Reducing drag is therefore desirable.
What are the two main types of Drag?
Parasite Drag and Induced Drag
What is parasite drag?
The drag not associated with lift, and subdivided into Profile Drag & Interference Drag.
How many forms of profile drag are there?
Two.
Skin Friction
Form Drag
Describe Skin Friction
A type of profile drag, which itself is a type of Parasite Drag.
The friction forces existing between an object and the air through which it is moving.
Describe Form Drag
A type of profile drag, which itself is a type of Parasite Drag.
Form drag is caused by the separation of the boundary layer from a surface and the wake created by that separation.
What is Interference Drag?
A type of Parasite Drag.
Drag that is generated by the mixing of airflow between airframe components such as the wing and the fuselage.
What is induced drag?
The unavoidable by-product of lift which increases as the angle of attack increases.
Which type of drag is the most important to ATC?
Induced Drag
Where is induced drag produced?
Produced at the wingtips where there is a spillover of high pressure air from beneath to above the wing, creating wingtip vortices.
When lift increases, what happens to induced drag?
Induced drag increases as lift increases.
If a wing is not generating lift, is there any induced drag?
No
Operationally, when are wing tip vortices considered to exist from and to?
Vortices are considered to exist from when the nosewheel lifts on take off until it touches down on landing.
When is induced drag at its greatest?
When an aircraft is flying slowly, at a heavy weight and in a ‘clean’ configuration, such as in the early stages of a climb.
